Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 50: Gallium Nitride: Fabrication and Characterization

HL 50.4: Vortrag

Mittwoch, 9. März 2016, 10:15–10:30, H17

Germanium doping of cubic GaN — •Michael Deppe¹, Jürgen W. Gerlach², Dirk Reuter¹, and Donat J. As¹ — ¹Universität Paderborn, Department Physik, Warburger Straße 100, 33098 Paderborn — ²Leibniz-Institut für Oberflächenmodifizierung e.V., Permoserstraße 15, 04318 Leipzig

Up to now the most commonly used n-type dopant for cubic GaN is silicon. We present a study of germanium as an alternative n-type dopant. The germanium doped cubic GaN films were grown on 3C-SiC/Si (001) substrates by plasma-assisted molecular beam epitaxy. The incorporation of germanium into the GaN films could be verified using secondary ion mass spectrometry (SIMS) and Hall effect measurements revealed the electrical properties of the samples. Films with doping densities above 3 · 10¹⁸ cm⁻³ exhibit n-type conductivity whereas films with lower doping densities are p-type due to electrically active dislocations. A maximum electron concentration of 3.7 · 10²⁰ cm⁻³ was achieved. From a comparison of SIMS and Hall effect measurements we conclude that in the highest doped sample not all incorporated dopants are electrically active. For doping densities in the order of 10¹⁹ cm⁻³ and above, a degradation of the crystal quality was observed by high resolution x-ray diffraction (HRXRD). Furthermore, a comparison to silicon doped films reveals no significant differences.